Question

Problem 4.067 SI The figure below provides steady-state data for a throttling valve in series with a heat exchanger. Saturated liquid Refrigerant 134a enters the valve at a pressure of 9 bar and is throttled to a pressure of P = 2 bar. The refrigerant then enters the heat exchanger, exiting at a temperature of 10°C with no significant decrease in pressure. In a separate stream, liquid water at 1 bar enters the heat exchanger at a temperature of 25°C with a mass flow rate of 14 = 3 kg/s and exits at 1 bar as liquid at a temperature of 15°C. Stray heat transfer and kinetic and potential energy effects can be ignored. Heat exchanger e Saturated to m ? ooc Saturated - liquid R-134a at P. = 9 bar Valve P2 WWWA +5 +4 4 Ts = 15°C Ps = P4 Water T4 = 25°C P4 = 1 bar Determine: (a) the temperature, in °C, of the refrigerant at the exit of the valve. (b) the mass flow rate of the refrigerant, in kg/s.

Answer 1

GD MYM0 Saturatf LLg T 1s @ The Tep (t) ,te Refrigegt at exit of valve Process EL-2) Turotrling process Diring process 4, = 42_ Tt is Satyrared liguid at g bqr AT Stup-o 99.S6 Pressure Tatle for R3u So 99. S k 24130 So we Cam Soit īs satyravzq mix at See 2 State-02 T Teat 269r =-/0 0g T2= -10.09 Ausuore Temp ateriE Of value

OMass flo rale of refir gesent () = 2bar is suphey heskd So t Tsat 6u -lo.092 vajpou at Sare-os, from super henks table at B = e 2 be anel h 258.89 leT For HEar eneclguger Heat gean b1 R-134 q Heat veleace by Coling walen ri(hh2) vioxpx ( T-7.) 2 4.2 for waKV Cp D ir258.8I-99. 54) = 2x 4.2x (z5-1s) nir I59.33 O-7908 Mass Flou rate of refrigerent Rr13Y 7